Developingcountries(LMICs)havetheworld?shighestprevalenceofdisablinghearingloss,but hearinghealthcareservicesareoftenunavailable,sparseandsporadic.Asolutiontothisneed- supplymismatchmaybetheincreasingpenetrationofsmartphonesthatwehypothesizeare capableofdeliveringaself-containedsolutiontothemostcommonformsofdisablinghearing loss.IntheRepublicofSouthAfrica(RSA),forexample,nearly80%ofthepopulationhave accesstoasmartphone.OnWorldHearingDaythisyear,anational,freehearingtestinthe formofasmartphoneapp(hearZA)waslaunchedinRSAwith>7000teststakeninthefirst week.HearZAdeliversadigits-in-noise(DIN)testbinaurallyinjust3minutesthathasbeen validatedagainst?better-ear?conventionalaudiometry(sensitivity,specificityboth>90%).The appallowsthosefailingthetesttorequestacontactfromtheirclosestaudiologist.DINtests providesuccessivespeechstreamsofthreedigits(0-9)adaptivelydeliveredagainstabroad- band(?white?)noise.Theyarereliableandmaybeself-administeredwithoutasoundboothby enteringthedigitsheardonthesmartphonekeypad.Thepurposeoftheproposedresearchisto developfurtherfunctionsforhearZAenablingenhancedassessment,advice,andasimulation ofthebenefitthatamplificationcouldprovide?allonthesamesmartphone.Theaimsofthe researchare(i)toimprovedetectionofhearingloss,includingunilateralhearingloss,without increasingtesttime.Thiswillbeachievedusinginteraurallyantiphasicdigitstimuli;?(ii)to increasesensitivitytohearinglossusinghighpassnoisefiltering,andtointroducemonaural, follow-uptesting;?(iii)tosupportreferralbyaddingashortquestionnaireanduptakeof interventionsusinganin-appdecision-supporttool;?and(iv)todeterminethebenefitofcarefully selectedsimulationsofamplificationandnoisereductionavailableassmartphone?personal soundamplification?apps.Benefitwillbedeterminedusingbothobjectivetestsofhearingin noiseandpatient-centeredbenefitassessment.Multinomialregressionmodelingwillrelate resultsacrosstheaims.ThesuccessofhearZAdemonstratestheresourcesavailableinRSAto makethisproposalwork.Althoughapplicableworldwidetoallsmartphoneusers,thisapproach isuniquelysuitedtoLMICsbecauseofthelackofalternatives.CollaborationwithotherLMICs inAfricaandelsewhereisalreadyunderway.